This invention relates to the field of swimming pools and especially to spa or therapeutic type pools and more particularly is directed to the outlet or drain portion of the pool.
In any pool a suction is generated around the drain when the pump is operating. In therapy spa pools the volume of water pumped through the drain is quite high, as large quantities of water are being rapidly recirculated back to the pool for therapeutic purposes. It has become increasingly evident through a series of unfortunate experiebces bt various persons utilizing therapy pools that a serious safety concern in posed by the extreme suction created in the drain outlet by the high velocity water. It has been found that, when a portion of a person's body becomes positioned adjacent the drain, the blockage over the drain by the person's body creates a tremendous suction on his body which causes discomfort and, in some instances, essentially holds the person to a position adjacent the drain. This is quite critical in the case of smaller children who do not have sufficient strength in which to push away from this suction which holds them to the bottom of the pool. In some cases, panicked children have drowned.
Another drawback to the existing drain designs utilized not only in therapeutic pools, but also in normal swimming pools, is the tendency for a significant amount of dirt particles to collect in the area adjacent the drain. This is due to the fact that the dirt particles settle to the bottom of the pool and that most of the water which is drawn into the drain comes from a point above the bottom of the pool, leaving the dirt particles to remain in an essentially stagnant area of the pool around the drain.